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Aphidiusmatricariae, a braconid wasp, parasitizing an aphid.

Aphidius matricariae. This Vi6 inch (2 mm) long, black braconid wasp from Europe is one of the most common and effective parasites of the green peach aphid.A.matricariae is not a good parasite of cotton aphid or potato aphid. Females lay 50-150 eggs singly in aphid nymphs of all sizes.The wasp larvae consume the aphids from inside. As the larvae mature and the aphids are killed, over about 7-10 days, the aphids turn into mummies—smooth, shiny, and light brown to silvery-gold. After the larvae pupate, each adult wasp emerges in about 5 days through a round exit hole cut in the mummy. In addition to killing aphids directly, mechanical disturbance of aphid colonies by the searching activity of the adult wasps causes many aphids to fall off the plants and die.This wasp is available commercially.

The midge Aphidoletes aphidimyza. Females can lay up to 250 eggs among aphid colonies.

Diaeretiella rapae. This cosmopolitan aphidiid species, probably native to Europe, is normally a parasite of the cabbage aphid, Brevicoryne brassicae, but it readily attacks green peach aphid in the greenhouse. Females lay an average of 85 eggs during their lifetime and prefer half-grown nymphs over first instars or adults. Parasitized aphids become golden brown mummies.This insect is sold commercially.

Ephedrus cerasicola. This European aphidiid wasp parasitizes green peach aphid.The aphids become black mummies about 12 days after the female oviposits in the aphids.The parasitized aphids often move from the plant to the pot or support structures before becoming mummies.The adult wasps emerge about a week after mummies appear.E.cerasicola is not yet commercially available in North America.

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Lysiphlebus testaceipes. This aphidiid wasp is an effective parasite of all instars of cotton aphid, but not of green peach aphid or potato aphid.The aphid mummies are yellowish brown to brown. It is adaptable to a range of climatic conditions.This wasp is commercially available.

Predators

Aphidoletes aphidimyza. The larvae of this midge feed on over 60 aphid species, including all that occur on greenhouse crops.The adults are small—less than 1/i6 inch (2 mm) long—black, delicate flies, similar in appearance to fungus gnats, that live for an average of 10 days by feeding on aphid honeydew.They hide beneath the leaves during the day and are active at night. Females deposit 100-250 tiny (less than 1/64 inch, or 0.3 mm), shiny orange eggs singly or in small groups among aphid colonies.The bright orange, slug-like larvae that hatch in 2-3 days inject a toxin into aphids' leg joints to paralyze them, then they suck out the aphid body contents through a hole chewed in the thorax.The larvae grow up to 1/8 inch (3 mm) long and each kills 4-65 aphids per day. Larvae can consume aphids much larger than themselves and may kill many more aphids than they eat when aphid populations are high. After 3-7 days, the larvae drop to the ground

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